Slurry pump



July 26, 1966 A. w. KINGSBURY 3,262,396.

SLURRY PUMP Filed Nov. 9, 1964 2 Sheets-Sheet 1 FIG-l FIG-2 July 26,1966 A. w. KINGSBURY SLURRY PUMP 2 Sheets-Sheet 2 Filed Nov. 9, 1964United States Patent O of New York Filed Nov. 9, 1964, Ser. No. 403,765

9 Claims. (Cl. 103-240) This invention relates to a pump for slurryconsisting of a granular solid and a liquid, and it comprises a pumpchamber, a slurry supply tank, a slurry receiving tank, a pipeinterconnecting said supply tank and a supply of liquid, a pipeinterconnecting said supply tank and said pump chamber, a pipeinterconnecting said pump chanb'er and a po nt of disposal, a pipeinterconnecting said pump chamber and a supply of liquid, a pipeinterconnecting said receiving tank and said pump chamber, valve meansin each of said pipes, control means for the valve means in the firstnamed three pipes, other control means for the valve means in the lastnamed two pipes, and timing means adapted to actuate said control meansto alternately open the valve means in the first name-d three pipes andthose in the last named two pipes, all as more fully set forthhereinafter and'as claimed.

In many industrial processes it is necessary to transfer predeterminedquantities of slurry from one tank to another. Thus, in modern liquidtreatment, as for instance water softening by ion exchange, a slurry ofresin is transferred in controlled quantities from a treatment tank to aregenerator, thence to a rinse tank and finally back to the treatmenttank. However, this application for a slurry pump has been referred toby way of example only as the requirement to transfer predeterminedquantities of slurries exists in other fields as well. Conventionalpumps are generally not suitable for such transfer.

It is an object of this invention to provide an effective and reliablepump which transfers a predetermined quantity of slurry in eachoperating cycle.

Another object is to provide a pump operating in cycles of alternatelyintroducing slurry into and withdrawing slurry from a pump chamber, withmeans for controlling each step of the cycles.

Still another object is to provide control means by which the step ofWithdrawing slurry from the pump chamber is terminated by thedisappearance of slurry from a predetermined location in the pump.

Other objects, novel features and advantages will appear from thefollowing description.

The manner in which these objects are achieved is shown in the appendeddrawings in which:

FIG. 1 is a more or less diagrammatic showing in elevation and partly incross section of one embodiment of my invention;

FIG. 2 is a fractional view showing a modification of a portion of theapparatus shown in FIG. 1;

FIG. 3 is a view, similar to FIG. 1, of another embodiment of myinvention; and

FIG. 4 is a view of a modification of the pump shown in FIG. 3.

Referring now to FIG. 1, my novel pump has a pump chamber with a dishedbottom 11 and a top 12 to which is attached a strainer 13. On oppositesides the pump chamber 10 has oblong transparent windows 14 and 15.Adjacent to window 14 is a light source 16 and adjacent to window 15 isa photoelectric cell- 17. The source 16 thus projects light through thewindows 14 and 15 and the interior of the pump chamber 10 towards thephotoelectric cell 17 which is provided with a switch which is closedwhen slurry between windows 14 and 15 obstructs the light projectedtowards the cell 17, and which opens when light from source 16 reachesthe cell 3,262,396 Patented July 26, 1966 17 upon the disappearance ofslurry. The apparatus includes a slurry supply tank 18 and a slurryreceiving tank 19.

A pipe 20 with valve 21 leads from a supply of liquid under pressure(not shown) to the supply tank 18. A pipe 22 with valve 23 interconnectsthe bottom of supply tank 18 and the top 12 of the pump chamber 10. Apipe 24 with valve 25 leads from the strainer 13 to' a point of disposalfor liquid. A pipe 26 with valve 27 leads from supply of liquid underpressure to the pump chamber 10, being conveniently joined to pipe 24,as shown. A pipe 23 with valve 29 interconnects the lowest point of thesloping bottom 11 of the pump chamber 10 with the slunry receiving tank19. The numeral 30 refers to slurry in the pump chamber 10.

The main valves 21, 23, 25, 27 and 29 have operators for controllingtheir opening and closing, preferably in the (form of diaphragm chambersas shown, which include a spring urging them to valve closing positionand which are adapted to open the valve on admission of fluid underpressure to the diaphragm chamber and close the valve when the diaphragmchamber is vented. Valves 23 and 29 which handle slurry should be, andthe other main valves may be of a type which has a minimum of tortuouspassages in which solids from the slurry may settle out, accumulate andthus obstruct free flow through the valve when it is open; they should,furthermore, not have a member movable towards and away from a seatbecause solid particles from the slurry may get caught between such seatand movable member and thereby interfere with tight closing. Valves ofthe type generally known as ball valves meet these requirements and arewell suited for use in my slurry pump.

The control means for the main valves include solenoid pilot valves 31,32 and 33. These are of the so-called three-way type, as for exampleshown in US. Patent 2,614,584 dated October 21, 1952. Each of thesesolenoid valves 31, 32 and 33 has a common port and connection C, anormally closed port and connection NC connected by a pipe 34 to asource of fluid under pressure and a normally open port and connectionNO connected by a pipe 35 to a point of disposal for pressure fluid. Thepressure fluid supplied to pipes 34 may be a liquid, for instance water,or it may be'a gas, as for example air. In the latter case the pipes 35may simply be vented to the atmosphere. When the fluid is a liquid thepipes 35 lead to a suitable point of disposal. Such liquid may, ofcourse, be recovered for re-use. The common port C of solenoid valve 31has a connection 40 with main valve 21, that of solenoid valve 32 has aconnection 41 with branches leading to main valves 23 and 25, and thatof solenoid valve 33 has a connection 42 with branches leading to mainvalves 27 and 29. Thus, when any one of the solenoid valves 31, 3'2 and33 is de-energized the diaphragm chamber of the main valve with which itis connected is vented through the communicating ports and connections Cand NO, and the main valve stays closed. When the solenoid valve isenergized or activated pressure fluid is admitted to the diaphragmchamber of the main valve through the communicating ports andconnections C and NC and the main valve opens, remaining open as long asthe solenoid valve remains energized, and closing upon de-energizationof the solenoid valve.

Timing means are provided to alternately energize solenoid valves 31 and32 on the one hand and solenoid valve 33 on the other hand. These timingmeans include time switches 43 and 44 and a counter 45. The timeswitches 43 and 44 are of the type which upon motivation maintains itsswitch closed for a predetermined and adjustable intervial of time andthereupon opens its switch and sends out an impulse or signal, holdingitself ready to repeat this performance 'upon re-motivation.

The counter 45 is of the type which counts and registers the impulse itreceives and which is capable of passing on an impulse for everyonereceived up to a preset and adjustable number of impulses received, andof repeating this performance upon re-motivation or re-setting.

The time switch 43 has a connection 46 to solenoid valves 31 and 32whereby they .are adapted to be energized in unison by the closing ofthe time switch 43. The time switch 44 has a connection 47 to thesolenoid valve 33 with a branch 48 to the switch of the photo-electriccell 17. The time switch 43 also 'has a connection 49 to the time switch44, and the latter has a connection 50 to the counter 45 which in turnhas a connection 51 running to the time switch 43.

It should be noted that for the sake of simplicity in presentation andease in understanding the connections 46 to 51 represent functionalconnections between the several electrical elements. In the actualwiring the switch of the time switch 44 and the switch of thephotoelectric cell 17 are arranged in series with the solenoid valve 33so that the latter is energized only when both these switches are closedand de-energized when either switch opens.

The solenoid valves 31 and 32 are connected in parallel so that they areenergized and de-energized in unison by the time switch 43.Alternatively, a single solenoid valve could be .substituted to controlall three main valves 21, 23 and 25. However, it is sometimes moreconvenient to use several solenoid valves operating in unison becausethis facilitates testing and adjusting and also because solenoid valvesare more readily available com mercially with relatively smallcapacities than with the larger ones required for the control of severalmain valves, especially those having'operators of substantial size.

Operation of the slurry pump shown in FIG. 1 is as follows. The quantityof slurry 30 shown in the pump chamber is such that it has disappearedfrom the location in which it obstructs the light projected from thesource 16 onto the cell 17. The cell 17 has therefore opened its switch,thereby de-energizing the solenoid valve 33 so that main valves 27 and29 are closed. Main valves 21, 23 and have been closed previously sothat there is now no flow through the apparatus. Time switch 44 is stillin its motivated position, but shortly will reach the end of its presettime interval whereupon it opens its i switch and sends an impulsethrough the connection 50, thereby motivating the counter 45. Theopening of time switch 44 produces no effect because the seriesconnected switch of cell 17 has already opened, thereby de-energizingthe solenoid valve 33.

On motivation the counter 45 sends an impulse through connection 51 tothe time switch 43 which is thereby motivated to energize solenoidvalves 31 and 32 through connection 46. This causes pressure fluid to beadmitted from pipes 3-4 through the respective connections 40 and 41 tothe diaphragm chambers of valves 21, 23 and 25, causing them to open.Now liquid under pressure enters through pipe 20 into the supply tank18, fluidizing the slurry therein, and fluidized slurry flows throughpipe 22 into the pump chamber 10 wherein it settles, the

excess of fluidizing liquid flowing out through strainer 13 and pipe 24.As the level of slurry in the pump chamber 10 rises it obstructs thelight projected from the source 16 upon the cell 17 and the switch ofcell 17 closes.

However, this produces no immediate effect because the series connectedtime switch 44 has in the meantime opened. When the pump chamber 10 hasbeen completely filled with slurry no more slurry can enter butfluidizing liquid. continues to come in through pipe 22 and leaves the.pump chamber 10 through strainer 13 and pipe 24.

Since the rate of flow of slurry through pipe 22 may vary somewhat fromcycle to cycle the time switch 43 is set to allow a small extra marginof time to insure that the pump chamber 10 is completely filled withslurry during every operating cycle. When the time interval for whichtime switch 43 has been set has expired it deenergizes solenoid valves31 and 32 and sends an impulse through connection 49, motivating timeswitch 44.- The de-energization of the solenoid valves 31 and 32 ventsthe diaphragm chambers of main valves 21, 23 and 25 through pipes 34,and 40 and 41, respectively, and these three main valves close.

The motivation of time switch 44 causes its switch to energize solenoidvalve 33 so that the main valves 27 and 29 open. Now liquid underpressure enters through pipe 26 (including a portion of pipe 24) andstrainer 13 into the pump chamber 16 and pushes the slurry 30 throughpipe 28 into the receiving tank 19. When the slurry 30 in the pumpchamber 10 has dropped to the level shown in FIG. 1 it permits lightfrom the source 16 to reach the photo-electric cell 17 which thereuponopens its switch, de-energizing solenoid valve 33 which in turn closesthe main valves 27 and 29 thereby stopping the transfer of slurry fromthe pump chamber 10 to the receiving tank 19. This completes the cycleof operations. From time to time or more or less continuously and by anysuitable means not shown in the drawing more slurry to be pumped istransferred into the supply tank 18 and the pumped slurry is removedfrom the receiving tank 19.

As the foregoing description makes clear, in each operating cycle thepump chamber 10 is alternative-1y completely filled with slurry andemptied of slurry to a level determined by the location of light source16 and photoelectric cell 17. If these are raised or lowered adjacent tothe windows 14 and 15, made oblong to permit such adjustability, thequantity of slurry pumped during each operating cycle may be decreasedor increased, respectively.

Since the pump thus transfers a fixed quantity of slurry during eachoperating cycle, predetermined by the positioning of the light source 16and the photo-electric cell 17, the counter 45, by registering thenumber of operating cycles, constitutes a meter for the quantity ofslurry pumped. If the counter 45 sends an impulse to time switch 43every time it receives and counts an impulse from time switch 44operation of the pump is continuous. However, the counter 45 ispreferably of the type which may be optionally set or adjusted so thatafter receiving and counting a pre-selected number of impulses receivedfrom time switch 44 it sends no impulse to time switch 43, therebystopping operation of the pump. This performance may then be repeated byre-setting or activating the counter 45 which can be done manually orautomatically by the use of an additional timer or other control device.

The liquid supplied to pipes 20 and 26 for fluidizing and transferringthe slurry may be water or some other suitable liquid. When the pump isused in ion exchange liquid treatment spent regenerating liquid may beused for this purpose to good advantage. When the liquid is clear, likewater, it is best to provide the light source 16 with means to project aconcentrated beam of light towards the cell 17. When the liquid'ismilky, however, like spent brine, it is better to employ as light source16 a flood light which, aided by the opalescence of the spent brine,tends to light up all or most of the interior of the pump chamber 10. Ineither case the absence or presence of slurry in the region between thewindows 14 and 15 determines whether or not light reaches thephoto-electric cell 17 and whether the switch of cell 17 is open orclosed, respectively.

In the interest of good functioning of the pump it is important that themain valves opened in one step of the cycle are fully closed before theother main valves open in the next step. At the end of the pump chamberemptying step this is inherent in the construction shown in FIG. 1because the photo-electric cell 17 de-energizes solenoid valve 33,resulting in the closing of main valves 27 and 2? before the time switch44 reaches the end of its time interval and sends an impulse bring aboutthe opening of main valves 21, 23 and 25. It may, however, be necessaryto employ special means such as a time delay relay to delay eithersending an impulse to time switch 44 or the energization of solenoidvalve 33 at the end of the pump chamber filling step in order toprovidethe time interval necessary for main valves 21, 23 and 25 to closebefore main valves 27 and 29 begin to open.

FIG. 2 shows a modification of a portion of the slurry pump illustratedin FIG. 1. Here the pump chamber has no Windows (14 and 15 in FIG. 1)and in lieu thereof the pipe 28 is provided with a transparent section55 adjacent to the pump chamber 10. The light source 16 and thephoto-electric cell 17 are located on opposite sides of the transparentsection 55. Thus, the photo-electric cell 17 is responsive to theappearance and disappearance of slurry in pipe section 5-5. Because ofthe relatively small cross-section of the latter no significantadjustment of the quantity of slurry pumped during each operating cyclecan be attained by raising or lowering the light source 16 andphoto-electric cell 17, as in FIG. 1. To provide such adjustabilitywithout changing the size of pump chamber 10 the pipe 22 communicateswith an extension 56 terminating at a level L. In this modification pipe24 including valve 25 is connected with the bottom 11 instead of top 12and provided with a strainer 57 to prevent escape of slurry when excessliquid is dischargedthrough pipe 24 during the pump chamber fillingstep. As shown, pipe 24 is branched to pipe 28 between the lattersconnection with the bottom 11 and valve 29, pipe 26 remaining connectedwith stainer 13.

With this arrangement the inflow of slurry into the pump chamber 10 stopautomatically when the slurry 30 has reached the level L, because theslurry settled in the lower part of the pump chamber 10' upon reachingthis level acts as a valve and thus stops the admission of more slurryalthough some fluidizing liquid continues to enter the pump chamber 10through pipe 22 and flow out through strainer 57 and pipe 24 until thesolenoid valve 32 is de-energized by the time switch 43, closing mainvalves 23 and 25. This feature is described in more detail andspecifically claimed in my US. Patent 3,208,934 dated September 28,1965. The quantity of slurry pumped during each operating cycle may bead. justed by lengthening or shortening the extension 56, therebylowering or raising the level L.

Aside from the basic difference that in FIG. 1 the pump chamber 10 iscompletely filled with slurry during the filling step and emptied to apredetermined level during the emptying step whereas in FIG. 2 the pumpchamber 10 is filled to a predetermined level L in the filling step andcompletely emptied in the emptying step the two modifications operate ina similar manner, and the above description of the operation of theslurry pump shown in FIG. 1 applies to FIG. 2 as well.

Each of the modifications shown in FIGS. 1 and 2 has certain advantages.In FIG. 1 the adjustment of the quantity of slurry pumped in eachoperating cycle is simpler and more convenient. In FIG. 2, thetransparent pipe section 55 is simpler and less costly than the windows14 and 15 of FIG. 1, and the higher velocity of flow through the section55 tends to keep it scoured and clean.

In the embodiment of my invention shown in FIG. 3 many elements are thesame and function in the same manner as in FIG. 1, and such elementshave, therefore, been assigned the same reference numerals. Theprincipal difference is that in lieu of a photo-electric cell causingthe closing of the main valves a ball float 60 is employed toautomatically seat on the bottom outlet of the pump chamber 10 whensubstantially all slurry has been withdrawn. The density of the ballfloat 60 must be so selected that it floats in the slurry but sinks inthe liquid forming a constituent part of the slurry. For instance, whenthe slurry consists of cation exchange resin and water it has a densityof about 1.24 in the settled condition, and a density of approximately1.16 to 1.19 when fluidized by the addition of 25 to 50 percent morewater. For such slurry a ball float with a density of about 1.05 is usedwhich is somewhat higher than that of water and substantially lower thanthat of settled as well as fluidized slurry. A good way of making theball float is to use a ball of polyethylene (which has a densitysomewhat lower than 1.0) provided with a cavity closed by a flush pluginto which cavity lead shot may be inserted to adjust the overalldensity of the ball to the required value.

If in any particular use the densities of both the slurry and the liquidare subject to variations the ball float 60 should have an overalldensity which is greater than that of the liquid of the highest specificgravity encountered, but lower than the lowest density which the slurrymay have.

This apparatus includes an additional pipe 61 leading to a supply ofliquid under pressure and having a main valve 62 and a strainer 63. Pipe61 is branched to pipe 28 between the pump chamber 10 and valve 29 sothat it thus communicates with the bottom portion of the pump chamber10. There is also an additional solenoid pilot valve 64 similar to theothers, with a normally closed port and connection NC supplied withfluid under pressure through a pipe 34, a normally open port andconnection NO adapted to discharge through a pipe 35 to a point ofdisposal, and a common .port and connection C. The common port C ofsolenoid valve 31 has a pipe connection 65 with the diaphragm chambersof main valves 21 and 23, that of solenoid valve 32 has a connection 66with main valve 25, that of solenoid valve 33 has a connection 67 withmain valves 27 and 29, and that of solenoid valve 64 has a connection 68with main valve 62.

The timing means of FIG. 3 include a time switch 44 and counter 45 likethose in FIG. 1, and two additional time switches 70' and 71 each ofwhich has two separate switches which are opened and closed in unisonbut which otherwise operate in the manner described above for timeswitches 43 and 44.

The functional interconnections between the various electrical devicesare as follows. Connection 72 leads from one switch of time switch 70 tothe solenoid valve 31, and connection 73 from the other switch to thesolenoid valve 32. A connection 74 leads from the switch of time switch44 to the solenoid valve 33. Connection 75 leads from one switch of thetime switch 71 to the solenoid valve 32, and a connection 76 from theother switch to the solenoid valve 64. In the actual wiring theconnections 73 and 75 place the switches of time switches 7 0 and 71from which they lead in parallel circuits with each other so that thesolenoid valve 32 is energized when either of these switches is closed,and de-energized when both these switches are open. There are,furthermore, the following motivating connections: 77 from time switch70 to time switch 44, 78 from time switch 44 to time switch 71, 79 fromtime switch 71 to counter 45, and 80 from counter 45 back to the timeswitch 70.

The apparatus is shown in FIG. 3 in the condition prevailing at the endof the pump chamber emptying step. The switch of time switch 44 isclosed, solenoid valve 33 is energized, and main valves 27 and 29 areopen. The ball float 60, riding down on the top level of the slurry hadapproached the end of pipe 28 so closely that it was sucked down, thusstopping further outflow of slurry although some slurry, as shown at 30,still remains in the pump chamber 10. Since there is some slurry trappedet-ween the ball float 60 and the bottom 11 liquid entering through pipe26 continues to flow through the interstices in this trapped slurry andthrough pipe 28 into the receiving tank 19 for a short interval untilthe time switch 44 reaches the end of its preset time period, opens itsswitch thereby de-energizing solenoid valve 33 so that main valves 27and 29 close, and sends a motivating impulse through connection 78 totime switch 71.

The motivation of time switch 71 energizes solenoid valves 32 and 64,and main valves 25 and 62 open. Liquid under pressure now enters throughpipe 61 and a portion of pipe 28, not only pushing the ball float 60 upfrom the end of pipe 28 but also levelling off the small amount ofslurry remaining in the pump chamber 11 The liquid flows out throughstrainer 13 and pipe 24. This step requires only a fraction of a minute,and the time switch 71 is therefore adjusted to maintain its switchesclosed after motivation for such short time. When the end of that timehas been reached the time switch 71 opens, deenergizing solenoid valves32 and 64 so that valves 25 and 62 close. Flow through the pump chamberstops and the ball float 60 rides on the levelled off slurry.Simultaneously with the de-energization of solenoid valves 32 and 64 thetime switch 71 sends a motivating impulse through connection 79 to thecounter '45 which registers the operating cycle and passes a motivationimpulse through connection 80 to time switch 70.

The motivation of time switch 70 causes its switches to energizesolenoid valves 3-1 and 32 so that the main valves 21, 23 and 25 open.Fluidizing liquid enters into the supply tank 18 through pipe 20, andslurry flows through pipe 22 into the pump chamber 10. The fluidizingliquid passes out through strainer 13 and pipe 24. The ball float 60rides up on the slurry as it settles in the pump chamber 10, but inorder to insure this and prevent the possibility that the ball floatmight become buried in the slurry which would result in prematureclosing of the outlet by the ball float 60 in the following pump chamberemptying step it is necessary to introduce the slurry into the pumpchamber 10 at a rate of flow not less than about 0.85 gallon per minuteper square foot of horizontal cross sectional area of the pump chamber10. The time switch 70 has been set to maintain solenoid valves 31 and32 energized tor a short time longer than normally required to fill thepump chamber 10. Thus when the pump chamber 10 has been completelyfilled with slurry with the ball float riding against the top 12fluidizing liquid only continues to flow through pipes 20, 22 and 24 fora brief period where-upon the switches of time switch 70 open, solenoidvalves 31 and 32 are de-energized, main valves 21, 23 and 25 close, anda motivating impulse passes through connection 77 to time switch 44.

The motivation of time switch 44 energizes solenoid valve 33, mainvalves 27 and 29 open, and liquid entering pipe 26 pushes the slurryfrom the measuring chamber 10 through pipe 28 into the receiving tank19with the ball float 60 riding down on top of the bed of slurry. Whennearly all slurry has thus been removed from the measuring chamber 10the ball float 60 is sucked against the end of pipe 28, thus stoppingthe flow of slurry. This restores the condition initially described andcompletes the operating cycle which here includes three steps, the balllifting step taking place after the emptying step and before the fillingstep. This cycle is repeated indefinitely unless the counter 45 stopsoperation of the pump after a predetermined number of cycles, asdescribed above.

Without the ball float 60 there would be a flow of liquid into thereceiving tank 10 at an objectionably high rate of flow after the slurryhas been removed from the pump chamber 10 and before valves 27 and 29are closed. With the ball float 60 the resistance in the innerst ices ofthe slurry trapped between the ball float 60 and the bottom 11 restrictsthis flow to a relatively low and not objectionable rate.

In this embodiment substantially the entire content of the pump chamber10 is transferred during each operating cycle, the relatively smallquantity of slurry remaining on the bottom 11 at the end of the emptyingstep being practically constant from cycle to cycle. There is noadjustment of the quantity of slurry pumped per cycle.

FIG. -4 shows a modification of the slurry pump of FIG. 3 withadjustability of the quantity by the provision of an extension for thepipe 22, similar to extension 56 of FIG. 2, which may be shortened orlengthened to raise or lower the level L to which the pump chamber 10 istfilled with slurry during the filling step.

In this modification there is an additional pipe 91 leading to a pointof disposal and connected with pipe 61 so that it communicates throughportions of pipes 61 and 28 with pump chamber .10. Pipe 91 has a mainvalve 92 the diaphragm chamber of which is connected by a pipe 93 with'pipe 65 so that valve 92 is controlled by solenoid valve 31 to operatein unison with valves 21 and 23. The functional connections 73, 77 and79 of FIG. 3 are omitted and there are provided a motivating connection94 from time switch 70 to time switch 71 and a motivating connectionfrom'time switch 44 to counter 45.

In FIG. 4 the apparatus is shown in condition ready to commence theemptying step, the slurry 30 extending up to the level L even with thelower end of pipe 90, and the ball float 6E9 riding on the top stratumof this bed of slurry.

The emptying step is initiated by a motivating impulse from time switch71 through connection 78 to time switch 44 which causes the slurry to betransferred from the pump chamber 10 to the receiving tank 19 in themanner previously described in connection with FIG. 3. On expiration ofthe alotted time, with the ball float 60 in the position shown in FIG.3, the time switch 44 sends a motivating signal through connection 95 tocounter 45 which in turn motivates the time switch 70 through connection80.

Time switch 70 now energizes solenoid valve 31 and the main valves 21,23 and 92 open. -Fluidizing liquid flows through pipe 20 into supplytank 18, whence slurry passes through pipe 22 and extension 90 into thepump chamber 10 wherein it settles, burying the ball float 60. Thefluidizing liquid flows out through the interstices in the slurrytrapped between the ball float 60 and the bot tom 11, portions of pipes28 and 61, and pipe 91, and this flow continues even after the slurry 30has reached the level L and stops further admission of slurry throughextension 90, until at the end of its alotted time the time switch 70opens its switch, thereby de-energizing solenoid valve 31 so that mainvalves 21, 23 and 92 close, and sends a motivating impulse throughconnection 94 to time switch 71.

On such motivation time switch 71 energizes solenoid valves 32 and 64and main valves 25 and 62 open. Liquid entering through pipe 61 pushesthe ball fioat up from the end of pipe 28 and by its upward flow throughpump chamber 10 loosens the bed of slurry 30 so that the ball float dueto its buoyancy rises through the slurry until it floats in the topstratum of slurry, as illustrated in FIG. 4. The liquid flows outthrough strainer 13 and pipe 24. After the brief interval of timerequired for this operation the time switch 71 opens its switch,de-energizing solenoid valves 32 and 64 so that main valves 25 and '62close, and sends a motivating impulse through connection 7 8 to timeswitch 44. This completes the cycle of operations and initiates anotherone. This cycle, as in FIG. 3 consists of three steps but here the balllift-ing step is interposed after the filling step and before theemptying step.

The periods of time for which the several time switches are set depend,of course, on the quantity of slurry pumped per cycle, the size of themain valves and piping connected with the pump chamber and otherfactors. These time periods may be of the order of 1 to 2 minutes forthe filling and emptying steps and a fraction of a minute for the balllifting step (if a ball float is used). These time periods include foreach step the time required for the opening and closing of the valves.and the time needed to complete the particular operation plus an extramargin for safety.

In lieu of the hydraulic or pneumatic type (as shown) motorized mainvalves may be used. In that event the valve control means will includeelectric motors and limit switches, as well as means 'for reversal ofthe direction of rotation to effect alternating opening and closing ofthe main valves.

Separate time switches have been shown for the several operating stepsbecause time switches of a construction suitable for such use arereadily available commercially. However, a single timing device could besubstituted which combines the functions of the several time switches ina single mechanism.

When the pump is used in ion exchange treatment the slurry willgenerally consist of head resin or other granular ion exchange materialand water or spent regenerant, i.e. brine or acid in case of cationexchange and solution of alkali in case of anion exchange. The pump mayalso be employed to pump a slurry of activated carbon used forpurification of water, sugar solutions, etc. Other uses include thetransfer of slurries of granular solid catalysts or reactants to or fromreaction vessels or processes.

It should be noted that the ball float will only function satisfactorilyif there exists an appreciable difference between the density of theslurry and that of the liquid used. Referring in this connection to theabove mentioned uses [for my novel slurry pump, there is not asufiiciently large density difference when the slurry consists ofactivated carbon and water. Therefore, for pumping such slurry thearrangements of FIGS. 3 and 4 are not recommended, and the arrangementof FIG. 1 or 2 should be used.

While I have shown and described what I consider the best forms of myinvention modifications including those specifically referred to hereinand others may be made without departing from the spirit of myinvention, and reference is therefore made to the appended claims for adefinition of its scope.

What I claim is:

1. A pump for slurry consisting of a granular solid and a liquid,comprising a pump chamber, a slurry supply tank, a slurry receivingtank, a first pipe interconnecting said supply tank and a supply ofliquid, a second pipe interconnecting said supply tank and said pumpchamber, a third ipe interconnecting said pump chamber and a point ofdisposal, a fourth pipe interconnecting said pump chamher and a supplyof liquid, a fifth pipe interconnecting said receiving tank and saidpump chamber, valve means in each of said pipes, first control meansconnected and adapted upon actuation to open the valve means in saidfirst, second and third pipes, second control means con nected andadapted upon actuation to open the valve means in said fourth and fifthpipes, timing means connected with said control means and adapted toalternately actuate said first and second control means, said timingmeans comprising two separate timers each having switch means adaptedupon motivation of the timer to close for a predetermined interval oftime, each of said control means being connected with and adapted to beactuated by one of said switch means, and interconnections between saidtimers whereby each of said timers is adapted to motivate the other ofsaid timers.

2. In the pump of claim 1, a pump cycle counter interposed in one of theinterconnections between said timers.

3. A pump for slurry consisting of a granular solid and a liquid,comprising a pump chamber, a slurry supply tank, a slurry receivingtank, a first pipe interconnecting said supply tank and a supply ofliquid, a second pipe interconnecting said supply tank and said pumpchamber, a third pipe interconnecting said pump chamber and a point ofdisposal, a fourth pipe interconnecting said pump chamber and a supplyof liquid, a fifth pipe interconnecting said receiving tank and saidpump chamber, valve means in each of said pipes, first control meansconnected and adapted upon actuation to open the valve means in saidfirst, second and third pipes, second control means con nected andadapted upon actuation to open the valve means in said fourth and fifthpipes, timing means connected with said control means and adapted toalternately actuate said first and second control means, said timingmeans comprising two switches, said control means comprising three-waysolenoid valves each having a coil connected with and adapted to beenergized by one of said switches, a common port, a normally open portestablishing communication between said common port and a point ofdisposal and adapted to be closed upon energization of said coil, and anormally closed port adapted to be-opened upon energization of said coiland thereby establish communication between the common port and a supplyof fluid under pressure, pressure responsive operators for said valvemeans, and a connection from each of said pres sure responsive operatorsto the common port of one of said solenoid valves.

4. A pump for slurry consisting of a granular solid and a liquid,comprising a pump chamber, a slurry supply tank, a slurry receivingtank, a first pipe interconnecting said supply tank and a supply ofliquid, a second pipe interconnecting said supply tank and said pumpchamber, a third pipe interconnecting said pump chamber and a point ofdisposal, a fourth pipe interconnecting said pump chamber and a supplyof liquid, a fifth pipe interconnecting said receiving tank and saidpump chamber, valve means in each of said pipes, first control meansconnected and adapted upon actuation to open the valve means in saidfirst, second and third pipes, second control means connected andadapted upon actuation to open the valve means in said fourth and fifthpipes, timing means connected with said control means and adapted toalternately actuate said first and second control means, a switchoperated by said timing means, a light source and a photoelectric celladjacent to said pump chamber and arranged so that light is projectedfrom said light source onto said photo-electric cell and that slurrypassing through said pump chamber obstructs said light, and a secondswitch operated by said photo-electric cell in response to the presenceof slurry in said light, both said switches being wired in series withsaid second control means.

'5. In the pump of claim 4, transparent windows on opposite sides ofsaid pump chamber, said light source being located adjacent to one ofsaid windows and said photoelectric cell being located adjacent toanother of said windows on the opposite side of said pump chamber.

6. The pump of claim 4, said fifth pipe having a transparent portion,said light source and said photo-electric cell being located on oppositesides of said transparent portion.

7. A pump for slurry consisting of a granular solid and a liquid,comprising a pump chamber, a slurry supply tank, a slurry receivingtank, a first pipe interconnecting said supply tank and a supply ofliquid, a second pipe interconnecting said supply tank and said pumpchamber, a third pipe interconnecting sai-d pump chamber and a point ofdisposal, a fourth pipe interconnecting said pump chamher and a supplyof liquid, a fifth pipe interconnecting said receiving tank and saidpump chamber, valve means in chamber having a sloping bottom, said fifthpipe terminating in the lowest part of said sloping bottom, and a ballfloat in said pump chamber, said ball float having a density lower thanthe density of said slurry but higher than the density of the liquidforming a constituent part of said slurry.

1 1 8. In the pump of claim 7, a sixth pipe interconnecting a supply ofliquid under pressure and said fifth pipe at a location between saidpump chamber and the said valve means in said fifth pipe, and valvemeans in said sixth pipe.

9. In the pump of claim 8, third control means connected and adaptedupon actuation to open the valve means in said sixth pipe, said timingmeans being connected with said third control means and adapted toactuate said third control means for a predetermined period of time.

References Cited by the Examiner UNITED STATES PATENTS Bendz 10325 Welsh210-33 Goepfrich 251- 139 McGee 103-25 Higgins 21033 Linklater 103-240Kingsbury 210-33 MARK NEWMA N, Primary Examiner. W. J. KRAUSS, AssistantExaminer.

1. A PUMP FOR SLURRY CONSISTING OF A GRANULAR SOLID AND A LIQUID,COMPRISING A PUMP CHAMBER, A SLURRY SUPPLY TANK, A SLURRY RECEIVINGTANK, A FIRST PIPE INTERCONNECTING SAID SUPPLY TANK AND A SUPPLY OFLIQUID, A SECOND PIPE INTERCONNECTING SAID SUPPLY TANK AND SAID PUMPCHAMBER, A THIRD PIPE INTERCONNECTING SAID PUMP CHAMBER AND A POINT OFDISPOSAL, A FOURTH PIPE INTERCONNECTING SAID PUMP CHAMBER AND A SUPPLYOF LIQUID, A FIFTH PIPE INTERCONNECTING SAID RECEIVING TANK AND SAIDPUMP CHAMBER, VALVE MEANS IN EACH OF SAID PIPES, FIRST CONTROL MEANSCONNECTED AND ADAPTED UPON ACTUATION TO OPEN THE VALVE MEANS IN SAIDFIRST, SECOND AND THIRD PIPES, SECOND CONTROL MEANS CONNECTED ANDADAPTED UPON ACTUATION TO OPEN THE VALVE MEANS IN SAID FOURTH AND FIFTHPIPES, TIMING MEANS CONNECTED WITH SAID CONTROL MEANS AND ADAPTED TOALTERNATELY ACTUATE SAID FIRST AND SECOND CONTROL MEANS, SAID TIMINGMEANS COMPRISING TWO SEPARATE TIMERS EACH HAVING SWITCH MEANS ADAPTEDUPON MOTIVATION OF THE TIMER TO CLOSE FOR A PREDETERMINED INTERVAL OFTIME, EACH OF SAID CONTROL MEANS BEING CONNECTED WITH AND ADAPTED TO BEACTUATED BY ONE OF SAID SWITCH MEANS, AND INTERCONNECTIONS BETWEEN SAIDTIMERS WHEREBY EACH OF SAID TIMERS IS ADAPTED TO MOTIVATE THE OTHER OFSAID TIMERS.